Theft of services and goods has increased with the use of telephone access cards to credit telephone calls and the use of credit and other cards to obtain access by phone to personal accounts and to order goods. Unscrupulous observers, to obtain unauthorized access to phone services and credit accounts, will memorize card and PIN numbers while they are being entered either verbally through the mouthpiece of a phone or by keying them in with touchtone phone keys.
One way of avoiding exposure of card and PIN numbers is to use a portable autodialer. A portable autodialer can be a credit card sized device that can be kept in a wallet or pocketbook. They generate audible dial tone multifrequency (DTMF) signals for telephone and card numbers stored in the card for introduction into the mouthpiece of a telephone. There has been increased interest in autodialers with the increased use of telephone access cards. A standard telephone number has seven digits. A long distance telephone number has up to eleven digits. International dialing may require fourteen digits to access an overseas phone. Furthermore, a telephone access or credit card may have fourteen to sixteen digits. It is quite easy to miskey one of the many numbers that are required to be entered necessitating reentry of a long string of numbers.
The use of an autodialer eliminates the need for keying in large strings of numbers into a phone. The card and telephone numbers are stored in the autodialer. Just a few keystrokes are needed to activate the autodialer and select the correct telephone number. Once the autodialer is activated and the number selected, the card is held against the mouthpiece to enter the information in the form of DTMF tones into the telephone.
U.S. Pat. No. 5,377,263, filed Dec. 29, 1992 and entitled "Telephone Dialer Card" and U.S. Pat. No. 5,343,519, filed Sep. 7, 1993 and entitled "Autodialer with Pin Feature" disclose autodialers that transmit PIN numbers along with telephone access and credit card numbers. In both of these patents, the autodialers contain preprogrammed PIN numbers which are transmitted upon appropriate activation of the card. While such an arrangement prevents the previously mentioned unscrupulous observer from overhearing or seeing the numbers being entered, loss or misappropriation of the card can result in its unauthorized use. Furthermore, storing both card and pin numbers in the same device therefore obviates the intended advantage of having separate card and PIN numbers.